Thursday, June 25, 2015

Goathead Again!


Goathead thorn, or "nutlet", from my bike tire

I rode around for a few days with this thing stuck in my front tire. I saw the non-thorny seedy part stuck on it, and know pretty much what it was. Since I have sealant in my tires, these tend to poke in and form an airtight and well-stuck seal, and when they're not right in the tread, will stay there riding round and round somewhat harmlessly, at least for a while. If they're directly in the tread, on the other hand, the seedy part will usually grind right off, leaving only the thorn part behind, which sometimes stays stuck inside the tire poking a series of holes into the tube, or pops out, accompanied by a "hissssss" sound.

The thorns of this plant, Tribulus terrestris, known as "puncture vine" and a bunch of other names, are hard on bike tires. I've had several kevlar-based puncture layers on different tires punched right through by them. Only one I can think of it didn't go right through was a Continental Ultra Gatorskin, and I'm thinking Schwalbe Marathon Supremes might also hold up, but these little "nutlets" go through tough stuff--stuff that rejects tacks and glass regularly. Also, the geometry of the spike seems such that it often renders tire sealant ineffective.

At least I was able to wait until I was in my house, in the air conditioning, to pull it out and change the tube. After I pulled this one out of the tire, careful to not puncture my finger at the same time, I found another spike poking inside the tire casing, too, from another goathead, this one of the ground-off, directly in the tread type.

I've mentioned them on the blog before, of course, but didn't think I had a good photo of one. Now I do. There's something in there about "any ride might have its thorns," but I'm tired, and honestly just glad this one was easy to take care of, and that there don't seem to be too many out there. The large patches of the weed are recognized for the menace they are, and dealt with quickly, yet, somehow, the stray nutlet still shows up in my tire somewhat regularly. Seemingly more often when the weather turns blisteringly hot.
 


6 comments:

  1. One good thing about goatheads is the flats they cause are easily patched—usually without even needing to remove the entire tire from the rim.

    One nitpick: Tribulus terrestris. When using scientific names, the genus is capitalized and the species is not. See here: https://en.wikipedia.org/wiki/Binomial_nomenclature.

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    1. Fixed the scientific name, thanks! I will usually try to fix a flat without removing tire from rim, and without removing wheel from frame, because it often can be patched that way. When I do, though, I get this feeling like someone is watching me and disproving my shortcuts.

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  2. My god that thing is scary looking. Like an alien lifeform skeleton. Glad I'm not in Arizona. =)

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    1. The embryo embeds itself in the host, opportunistically travels along for miles on the host, then detaches to spawn a new colony.

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  3. Replies
    1. Fate, and anxiety of it, symbolized by a small seedpod.

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